The direction of causation is not clear but a little bit of anxiety might be good for your health. Depressed smokers must have terrible life expectancy.
A study by researchers at the University of Bergen, Norway, and the Institute of Psychiatry (IoP) at King's College London has found that depression is as much of a risk factor for mortality as smoking.
Utilising a unique link between a survey of over 60,000 people and a comprehensive mortality database, the researchers found that over the four years following the survey, the mortality risk was increased to a similar extent in people who were depressed as in people who were smokers.
Dr Robert Stewart, who led the research team at the IoP, explains the possible reasons that may underlie these surprising findings: 'Unlike smoking, we don't know how causal the association with depression is but it does suggest that more attention should be paid to this link because the association persisted after adjusting for many other factors.'
The study also shows that patients with depression face an overall increased risk of mortality, while a combination of depression and anxiety in patients lowers mortality compared with depression alone. Dr Stewart explains: 'One of the main messages from this research is that 'a little anxiety may be good for you'.
I expect people who are more prone to worry are also more prone to worry about their diet, their weight, the quality of the air they breathe, and other factors that influence their health. A worrier would be more likely to get tested for weird lumps and abnormal skin growths. A worries would be more likely to avoid developing unhealthy habits. So I'm not surprised by these results.
Fracturing rocks deep underground so that water can be heated up doesn't work well for generating geothermal energy. The US Department of Energy has decided to fund some national labs to develop an approach for geothermal energy capture involving carbon dioxide as a substitute for water. The approach offers the additional benefit of sequestering CO2.
In 2000, Los Alamos National Laboratory physicist Donald Brown proposed replacing water with supercritical carbon dioxide, a pressurized form that is part gas, part liquid. Supercritical CO2 is less viscous than water and thus should flow more freely through rock. Brown noted that a siphoning effect should help cycle the carbon dioxide, thanks to the density difference between the supercritical CO2 pumped down and the hotter gas coming up, slashing power losses from pumping fluid. Plus, Brown argued, instead of using precious fresh water resources, a carbon dioxide-based project could sequester the equivalent of 70 years worth of CO2 emissions from a 500 megawatt coal power plant.
In the on-going debate about substitutes for fossil fuels the main candidates are solar, wind, and nuclear. Geothermal just doesn't get much attention. Anyone know why?
Babies less prone to feel fear are more likely to commit crimes.
Even at the tender age of 3, children who will go on to be convicted of a crime are less likely to learn to link fear with a certain noise than those who don't. This may mean that an insensitivity to fear could be a driving force behind criminal behaviour.
Adult criminals tend to be fearless, but whether this characteristic emerges before or after they commit a crime wasn't clear, says Adrian Raine, a psychologist at the University of Pennsylvania in Philadelphia.
Will people choosing genetic alleles for their genetically engineered children make them more or less predisposed to feel fear than the average human today? The answer will at least partially determine whether embryo selection for preferred genes will make future humans more or less criminal than they are today.
Raine does a lot of interesting work on innate causes of behavior. See my posts Brain Scans Show Abnormalities In Psychopaths and Habitual Liar Brains Look Different On Scans for more interesting brain research from Raine.
Patients with heart disease in Norway, a country with no fortification of foods with folic acid, had an associated increased risk of cancer and death from any cause if they had received treatment with folic acid and vitamin B12, according to a study in the November 18 issue of JAMA.
Most epidemiological studies have found inverse associations between folate (a B vitamin) intake and risk of colorectal cancer, although such associations have been inconsistent or absent for other cancers, according to background information in the article. “Experimental evidence suggests that folate deficiency may promote initial stages of carcinogenesis, whereas high doses of folic acid may enhance growth of cancer cells. Since 1998, many countries, including the United States, have implemented mandatory folic acid fortification of flour and grain products to reduce the risk of neural-tube birth defects,” the authors write. “Recently, concerns have emerged about the safety of folic acid, in particular with respect to cancer risk.”
Med Page Today has a more detailed breakdown of the statistical results.
Foods naturally high in folic acid might still be beneficial since greens, for example, have lots of other nutrients in them. But efforts to convert refined foods into high vitamin foods might be problematic. Eat your greens and beans for higher folic acid in foods that have a lot of other things going for them.
People work harder on their current task when they have a tougher task coming up.
Consumers will work harder on a task if they're expecting to have to do something difficult at a later time, according to a new study in the Journal of Consumer Research.
In today's fast-paced world, consumers frequently undertake unrelated tasks in a sequence. An individual might make a grocery list, decide whether to take out a home improvement loan, search the Internet for a vacation spot, and choose a dinner location—all before preparing lunch. "It seems reasonable to expect that when consumers know that they will have to work hard on a future task, they will devote less effort to the current task, in order to save energy for the upcoming demanding task. This is not what we found," write authors Anick Bosmans, Rik Pieters (both Tilburg University, The Netherlands), and Hans Baumgartner (Pennsylvania State University).
In a series of five studies, the authors observed that the more difficult a future task was expected to be, the harder consumers worked on a current task. "For example, consumers consulted more information on a web page when they were asked to evaluate a new soft drink when they expected that they would later on have to work on a difficult and demanding task," write the authors. Other participants were better able to come up with weight loss ideas when they believed they would have to work hard on a future job.
I've noticed this in my own performance. Faced with a difficult task I'm more efficient at getting through easier tasks even when I do not need to complete the easier tasks before doing the difficult one.
If you want to raise your overall performance then consider giving yourself more challenging tasks to do.
CORVALLIS, Ore. – Researchers have discovered a genetic variation that may contribute to how empathetic a human is, and how that person reacts to stress. In the first study of its kind, a variation in the hormone/neurotransmitter oxytocin's receptor was linked to a person's ability to infer the mental state of others.
Interestingly, this same genetic variation also related to stress reactivity. These findings could have a significant impact in adding to the body of knowledge about the importance of oxytocin, and its link to conditions such as autism and unhealthy levels of stress.
Does the ability to read others cut or increase stress? I can see it cutting both ways. Sometimes obliviousness would be an advantage if everyone around you was anxious or depressed. Picking up on their signals would tend to bring you down. On the other hand, sometimes it is dangerous not to be able to read the emotional signals of others.
Can you read the minds of others?
One of the tests used to measure empathy included the "Reading the Mind in Eyes" test, created by Simon Baron-Cohen (cousin of actor/comedian Sacha Baron Cohen). Rodrigues said that this test is commonly used to discern how individuals can put themselves into the mind of another person, which overlaps with empathy, because it tests how well the participant can infer someone's emotional state by their eyes.
"In general, women do better on this test than men," Rodrigues said. "But we found a stark difference in both sexes based on the genetic variation." Those with the GG genetic variation were 22.7 percent less likely to make a mistake on the "Reading the Mind in the Eyes" test than the other individuals.
The article mentions a previous research report that found oxytocin spray given to autistics boosted the scores on behavioral and dispositional empathy measures. I'd like to know whether everyone would get a boost of greater social competence from a snort of oxytocin.
A variety of mental states have utility in different forms. Sometimes you just need to be a calculator. Sometimes you need to be a logic chopper. Other times you need to be a able to read people like a bunch of open books. It'd be helpful to be able to shift around into different useful mental states depending on the circumstances.
Okay, weeks have gone by without a vitamin D post. Well, with big turkeys on the horizon it is time to think about heart health. Patients over 50 years old with the lowest vitamin D levels died at higher rates.
MURRAY, UT – While mothers have known that feeding their kids milk builds strong bones, a new study by researchers at the Heart Institute at Intermountain Medical Center in Salt Lake City suggests that Vitamin D contributes to a strong and healthy heart as well – and that inadequate levels of the vitamin may significantly increase a person's risk of stroke, heart disease, and death, even among people who've never had heart disease.
For more than a year, the Intermountain Medical Center research team followed 27,686 patients who were 50 years of age or older with no prior history of cardiovascular disease. The participants had their blood Vitamin D levels tested during routine clinical care. The patients were divided into three groups based on their Vitamin D levels – normal (over 30 nanograms per milliliter), low (15-30 ng/ml), or very low (less than 15 ng/ml). The patients were then followed to see if they developed some form of heart disease.
Researchers found that patients with very low levels of Vitamin D were 77 percent more likely to die, 45 percent more likely to develop coronary artery disease, and 78 percent were more likely to have a stroke than patients with normal levels. Patients with very low levels of Vitamin D were also twice as likely to develop heart failure than those with normal Vitamin D levels.
Those are startling differences. But what is the direction of causation?
Researchers at Johns Hopkins are reporting what is believed to be the first conclusive evidence in men that the long-term ill effects of vitamin D deficiency are amplified by lower levels of the key sex hormone estrogen, but not testosterone.
In a national study in 1010 men, to be presented Nov. 15 at the American Heart Association's (AHA) annual Scientific Sessions in Orlando, researchers say the new findings build on previous studies showing that deficiencies in vitamin D and low levels of estrogen, found naturally in differing amounts in men and women, were independent risk factors for hardened and narrowed arteries and weakened bones. Vitamin D is an essential part to keeping the body healthy, and can be obtained from fortified foods, such as milk and cereals, and by exposure to sunlight.
"Our results confirm a long-suspected link and suggest that vitamin D supplements, which are already prescribed to treat osteoporosis, may also be useful in preventing heart disease," says lead study investigator and cardiologist Erin Michos, M.D., M.H.S.
Do you think you ought to take vitamin D but just do not seem to get around to starting the habit?
Out of the 60,000 vertebrate species still in existence an international group of scientists wants to sequence 10,000 of them.
Scientists have an ambitious new strategy for untangling the evolutionary history of humans and their biological relatives: a genetic menagerie made of the DNA of more than 10,000 vertebrate species. The plan, proposed by an international consortium of scientists, is to obtain, preserve, and sequence the DNA of approximately one species for each genus of living mammals, birds, reptiles, amphibians, and fish.
A bigger effort is needed to collect samples from many individual animals of each species so that their genetic diversity can be preserved in the face of declining numbers. Habitat loss is cutting into the numbers of many species. For some only the DNA samples will exist as the living species go extinct.
They think they can do this for about $5000 per species.
Known as the Genome 10K Project, the approximately $50 million initiative is “tremendously exciting science that will have great benefits for human and animal health,” Haussler said. “Within our lifetimes, we could get a glimpse of the genetic changes that have given rise to some of the most diverse life forms on the planet.”
The idea is to compare DNA sequences across the many vertebrate species to get idea of which genes can be traced back to common ancestors hundreds of millions of years ago. This effort will likely change the way that trees get drawn to show the relationships between species.
The orders of magnitude decline in DNA sequencing costs make this project possible.
The primary impetus behind the proposal is the rapidly expanding capability of DNA sequencers and the associated decline in sequencing costs. “We’ll soon be in a situation where it will cost only a few thousand dollars to sequence a genome,” Haussler said. “At that point, most of the cost will be getting samples, managing the project, and handling data.”
Too much selenium probably boosts blood cholesterol.
A new study from the University of Warwick has discovered taking too much of the essential mineral selenium in your diet can increase your cholesterol by almost 10%.
Selenium is a trace essential mineral with anti-oxidant properties. The body naturally absorbs selenium from foods such as vegetables, meat and seafood. However, when the balance is altered and the body absorbs too much selenium, such as through taking selenium supplements, it can have adverse affects.
A team led by Dr Saverio Stranges at the University's Warwick Medical School has found high levels of selenium are associated with increased cholesterol, which can cause heart disease.
In a paper recently published in the Journal of Nutrition, the research team examined the association of plasma selenium concentrations (levels of selenium in the blood) with blood lipids (fats in the blood).
The researchers found in those participants with higher plasma selenium (more than 1.20 µmol/L) there was an average total cholesterol level increase of 8% (0.39 mmol/L (i.e. 15.1 mg/dL). Researchers also noted a 10% increase in non-HDL cholesterol levels (lipoproteins within your total cholesterol that can help predict the risk of someone suffering a heart attack or chest pain). Also, of the participants with the highest selenium levels, 48.2% admitted they regularly took dietary supplements.
It is not easy to choose an optimal diet.
This reminds me of a study that illustrates the potential for genetic testing to optimize diet choices (nutrigenomics): Whether selenium helps or hurts against prostate cancer risk depends on which genetic variant you have for the enzyme manganese superoxide dismutase (SOD2). So Brazil nuts probably cut prostate cancer risk in some while boosting risk for others.
Higher selenium levels in the blood may worsen prostate cancer in some men who already have the disease, according to a study by researchers at Dana-Farber Cancer Institute the University of California, San Francisco.
A higher risk of more aggressive prostate cancer was seen in men with a certain genetic variant found in about 75 percent of the prostate cancer patients in the study. In those subjects, having a high level of selenium in the blood was associated with a two-fold greater risk of poorer outcomes than men with the lowest amounts of selenium.
By contrast, the 25 percent of men with a different variant of the same gene and who had high selenium levels were at 40 percent lower risk of aggressive disease. The variants are slightly different forms of a gene that instructs cells to make manganese superoxide dismutase (SOD2), an enzyme that protects the body against harmful oxygen compounds.
You can imagine how two different studies on selenium and prostate cancer could come to opposite conclusions if their patient groups had different distributions of SOD2 variants.
If you are a guy and can find a genetic testing service that will test for SOD2 variants you could find out whether you should eat high selenium foods or avoid them. I wonder whether these SOD2 variants modify the risks for other diseases.
Gina Kolata, writing in the New York Times talks to a lot of top medical researchers and reports on cancer-preventing drugs that go unused and the many disappointing diet and vitamin interventions for cancer prevention.
Many Americans do not think twice about taking medicines to prevent heart disease and stroke. But cancer is different. Much of what Americans do in the name of warding off cancer has not been shown to matter, and some things are actually harmful. Yet the few medicines proved to deter cancer are widely ignored.
The article does an excellent job of reviewing assorted great hopes for reduced cancer risk via diet and vitamins and how many of these approaches failed in large scale intervention trials. Biogerontologist Aubrey de Grey probably doesn't find this surprising since he argues that if micronutrients could deliver large benefits we'd probably carry mutations to up their concentrations in our bodies. There is a counter evolutionary argument though: an antioxidant in higher concentrations might make us less fit in the short term and therefore would have been selected against.
I'm willing to use drugs to cut cancer risks. The drugs finasteride and dutasteride (both used to stop hair loss and treat swollen prostates) would eliminate over a quarter of all prostate cancer cases per year if taken long term to protect against prostate cancer.
A large and rigorous study found that a generic drug, finasteride, costing about $2 a day, could prevent as many as 50,000 cases each year. Another study found that finasteride’s close cousin, dutasteride, about $3.50 a day, has the same effect.
Did she say $2 per day? I used a drug price comparison web site and found Costco selling finasteride for $1.19 per 5 mg tablet in quantity 100. A 10 year supply would set you back about $4400. Having helped someone die from prostate cancer that seems like a very low price to pay to avoid a horrible end. Heck, you can do even cheaper abroad and this is a generic drug. You won't be ripping off intellectual property by buying abroad.
I'm already tempted to ask a doctor to prescribe finasteride or dutasteride. Preserve hair, avoid prostatic hyperplasia (where the prostate slows urine flow), and avoid prostate cancer. I mean, why not? The side effects are said to wear off after a year. Any readers taking it? One concern: what other effects come from lowering dihydrotestosterone? Does regular testosterone also rise as a result?
Tamoxifen cuts the risk of breast cancer in half. An osteoporosis drug, Evista, does the same thing with fewer risks.
Then, in 1999, he had a chance to do another breast cancer prevention trial, this time of an osteoporosis drug, raloxifene, or Evista, which did not have the cancer drug taint. It was to be compared with tamoxifen.
The $110 million study, involving 19,000 women, ended in 2006. The two drugs were found to be equally effective in preventing breast cancer, but with raloxifene there was no excess uterine cancer and the clotting risk was 30 percent less.
Eating chocolate might be good for people whose metabolisms show up as stressed in blood tests. Though I have to wonder whether attacking the underlying causes of high stress hormones would be more likely to deliver a real benefit.
The "chocolate cure" for emotional stress is getting new support from a clinical trial published online in ACS' Journal of Proteome Research. It found that eating about an ounce and a half of dark chocolate a day for two weeks reduced levels of stress hormones in the bodies of people feeling highly stressed. Everyone's favorite treat also partially corrected other stress-related biochemical imbalances.
One big problem with research on benefits of food on health: research that turns up a positive result is more likely to get published than research that turns up a negative result. So the body of all published research has a bias toward showing benefits.
Another big problem: short term effects do not always translate into long term reduction of illness or death. We end up with lots of promising studies that suggest dietary practices which are unproven or disproved many years later. Long term research takes too long and is so expensive that the number of hypotheses that get tested by long term research ends up being pretty short.
This study reminds me of a third problem: Some studies produce positive results because they happen to use experimental subjects most likely to benefit. Subsets of people who have more stress, a lousier diet to start with, or other problems are probably more likely to benefit from a diet change. Should you eat chocolate? The answer might depend on your levels of stress hormones.
In the study, scientists identified reductions in stress hormones and other stress-related biochemical changes in volunteers who rated themselves as highly stressed and ate dark chocolate for two weeks. "The study provides strong evidence that a daily consumption of 40 grams [1.4 ounces] during a period of 2 weeks is sufficient to modify the metabolism of healthy human volunteers," the scientists say
So does eating chocolate deliver a benefit? I'm still not convinced. But at least with chocolate my taste buds think I ought to lower my standard of evidence.
Update: Big population studies of diet and health will become a lot more useful once it becomes affordable to genetically sequence each person. My guess is that in some of the studies that find a benefit from a dietary practice for some of the people in that study their genomes were well matched to the dietary practice under study. The inability to control for genetic endowment is one of the causes of positive results that fail to generalize to hold up in other studies.
Similarly, if we all had implanted nanosensors reporting our metabolic condition our cell phones could query our nanosensors, report the results to a web site, and then get back recommendations for, say, exercise or chocolate or cruciferous vegetables.
William Patterson of the University of Saskatchewan, says the Younger Dryas mini Ice Age came on in a matter of months.
JUST months - that's how long it took for Europe to be engulfed by an ice age. The scenario, which comes straight out of Hollywood blockbuster The Day After Tomorrow, was revealed by the most precise record of the climate from palaeohistory ever generated.
Around 12,800 years ago the northern hemisphere was hit by the Younger Dryas mini ice age, or "Big Freeze". It was triggered by the slowdown of the Gulf Stream, led to the decline of the Clovis culture in North America, and lasted around 1300 years.
Can our climate suddenly change drastically? Yes. We can't be assured of only slow gradual changes. Most of the time only slower changes happen. But rapid climate change is possible. For this reason I think we should develop the means to alter the climate on a global scale. We might some day need to reverse either a natural or human-made shift in climate.
The Younger Dryas also ended abruptly in 10 years.
Around 15,000 years ago, the Earth started warming abruptly after ~ 100,000 years of an "ice age"; this is known as a glacial termination. The large ice sheets, which covered significant parts of North America and Europe, began melting as a result. A climatic optimum known as the "Bölling-Allerød" was reached shortly thereafter, around 14,700 before present. However, starting at about 12,800 BP, the Earth returned very quickly into near glacial conditions (i.e. cold, dry and windy), and stayed there for about 1,200 years: this is known as the Younger Dryas (YD), since it is the most recent interval where a plant characteristic of cold climates, Dryas Octopetala, was found in Scandinavia.
The most spectacular aspect of the YD is that it ended extremely abruptly (around 11,600 years ago), and although the date cannot be known exactly, it is estimated from the annually-banded Greenland ice-core that the annual-mean temperature increased by as much as 10°C in 10 years.
That's an 18 F warming in ten years. Imagine your local climate changing that much that quickly.
Update: Some scientists think the Younger Dryas cooling was brought on by the bursting of the boundaries of a massive fresh water lake whose waters diluted the salt waters of the northern Atlantic Ocean and stopped the Gulf Stream. Therefore some argue we have no comparable plausible condition that can happen today to cause an equally sharp shift in climate. However, a massive upper atmosphere explosion of an asteroid is another possible explanation for the Younger Dryas. Such an asteroid collision with the Earth is certainly within the realm of the possible.
More generally, I think people have been lulled into complacency by a 20th century whose natural disasters were pretty mild. A century more like the 19th century is within the realm of the possible.
In a development that could have significant ramifications for the nation's health care system, Baby Boomers may well be entering their 60s suffering far more disabilities than their counterparts did in previous generations, according to a new UCLA study. The findings, researchers say, may be due in part to changing American demographics.
Have more obesity, less exercise, and other changes in diet and lifestyle begun to cut into life expectancies?
In the study, which will be published in the January 2010 issue of the American Journal of Public Health, researchers from the division of geriatrics at the David Geffen School of Medicine at UCLA found that the cohort of individuals between the ages of 60 and 69 exhibited increases in several types of disabilities over time. By contrast, those between the ages of 70 and 79 and those aged 80 and over saw no significant increases — and in some cases exhibited fewer disabilities than their previous cohorts.
While you can hear it widely said that medicine has made great advances those advances haven't been powerful enough to prevent other factors from making people less healthy. Now, some technological trends might well accelerate the rate of advance of medical technologies so much that rejuvenation therapies and other treatments will block and reverse the effects of dietary choices and poor lifestyle choices. But that hasn't happened yet. You really do have to take care of your body. You can't count on medicine to undo the damage caused by diet and lifestyle.
Update: WebMD has a more quantitative description of how much disability is increasing for people their 60s. The rises are pretty dramatic.
The tips of chromosomes are known as telomeres and they shrink in size every time a cell divides. Eventually the telomeres become short and interfere with cellular replication. This interference is probably an anti-cancer defense mechanism. At the same time, the shrinking of telomeres probably contributes to aging by reducing the ability of the body to make replacement cells to repair the body as we age. Well, old people with genetic variants that cause longer telomeres have a greater chance of living to age 100.
November 11, 2009 — (BRONX, NY) — A team led by researchers at Albert Einstein College of Medicine of Yeshiva University has found a clear link between living to 100 and inheriting a hyperactive version of an enzyme that rebuilds telomeres — the tip ends of chromosomes. The findings appear in the latest issue of the Proceedings of the National Academy of Sciences.
This is a surprising result because longer telomeres in old age might increase the risk of cancer.
If higher activity in telomere enzymes delays onset of cardiovascular diseases then this suggests that lack of ability to make replacement cells contributes to the development of cardiovascular disease.
More specifically, the researchers found that participants who have lived to a very old age have inherited mutant genes that make their telomerase-making system extra active and able to maintain telomere length more effectively. For the most part, these people were spared age-related diseases such as cardiovascular disease and diabetes, which cause most deaths among elderly people.
These results suggest to me that the ability to create safe youthful stem cells for implantation in our bodies might slow the aging process. I want lots of replacement cells with few harmful mutations and long telomeres.
